mode#
- scipy.stats.mode(a, axis=0, nan_policy='propagate', keepdims=False)[source]#
Return an array of the modal (most common) value in the passed array.
If there is more than one such value, only one is returned. The bin-count for the modal bins is also returned.
- Parameters:
- aarray_like
Numeric, n-dimensional array of which to find mode(s).
- axisint or None, default: 0
If an int, the axis of the input along which to compute the statistic. The statistic of each axis-slice (e.g. row) of the input will appear in a corresponding element of the output. If
None
, the input will be raveled before computing the statistic.- nan_policy{‘propagate’, ‘omit’, ‘raise’}
Defines how to handle input NaNs.
propagate
: if a NaN is present in the axis slice (e.g. row) along which the statistic is computed, the corresponding entry of the output will be NaN.omit
: NaNs will be omitted when performing the calculation. If insufficient data remains in the axis slice along which the statistic is computed, the corresponding entry of the output will be NaN.raise
: if a NaN is present, aValueError
will be raised.
- keepdimsbool, default: False
If this is set to True, the axes which are reduced are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the input array.
- Returns:
- modendarray
Array of modal values.
- countndarray
Array of counts for each mode.
Notes
The mode is calculated using
numpy.unique
. In NumPy versions 1.21 and after, all NaNs - even those with different binary representations - are treated as equivalent and counted as separate instances of the same value.By convention, the mode of an empty array is NaN, and the associated count is zero.
Beginning in SciPy 1.9,
np.matrix
inputs (not recommended for new code) are converted tonp.ndarray
before the calculation is performed. In this case, the output will be a scalar ornp.ndarray
of appropriate shape rather than a 2Dnp.matrix
. Similarly, while masked elements of masked arrays are ignored, the output will be a scalar ornp.ndarray
rather than a masked array withmask=False
.Examples
>>> import numpy as np >>> a = np.array([[3, 0, 3, 7], ... [3, 2, 6, 2], ... [1, 7, 2, 8], ... [3, 0, 6, 1], ... [3, 2, 5, 5]]) >>> from scipy import stats >>> stats.mode(a, keepdims=True) ModeResult(mode=array([[3, 0, 6, 1]]), count=array([[4, 2, 2, 1]]))
To get mode of whole array, specify
axis=None
:>>> stats.mode(a, axis=None, keepdims=True) ModeResult(mode=[[3]], count=[[5]]) >>> stats.mode(a, axis=None, keepdims=False) ModeResult(mode=3, count=5)